Electron transport in highly compensated,plastically bent,n-type InSb in the temperature range 4.2–300 K

Measurements of the Hall coefficient, dc electrical conductivity, and magnetoresistance have been made on two highly compensated, plastically bent,n-type InSb samples from liquid helium to room temperature. The number and Hall mobility of charge carriers and the electrical conductivity are greatly affected by plastic bending. The mobility decreases appreciably and the number of charge carriers increases in both the deformed samples. This increase of effective charge carriers can be attributed to the introduction of effective donor centers due to plastic bending. The electrical conductivity in one of the deformed samples increases between the temperature ranges 4.2–15 K and 125–190 K compared to that of the undeformed state of the sample. This unusual increase in is attributed to the large increase inn value. The magnetoresistance at 4.2 K is due to impurity-band conduction and is found to be positive. It shows approximately a linear variation with magnetic field in both the deformed samples. The observed behavior of the magnetoresistance at 300 K is consistent with the behavior expected for free electrons. The observed / at 77.4 K is found to be less than that at 300 K and is explained in terms of the Hall mobility values at these two temperatures.     

A multi-echelon production–inventory system with supply disruption

The article investigates an integrated multi-layer supply chain model consisting of supplier, manufacturer and retailer while supply disruption, machine breakdown, safety stock, maintenance breakdown occur simultaneously. At beginning of the production, manufacturer keeps some raw materials in stock received from second supplier at high price, as safety stock due to supply disruption of first supplier. Corrective maintenance is done immediately to restore its normal stage when machine breakdown occurs. Stock out situations at manufacturer and retailer are considered due to disruption of production for machine breakdown. The integrated expected costs of the chain in centralized (collaborating) and decentralized (Stakelberg approach) system are compared. A numerical example and its sensitivity analysis are provided to test feasibility of the model.     

Three stage trade credit policy in a three-layer supply chain–a production-inventory model

The main purpose of this paper is to investigate the optimal replenishment lot size of supplier and optimal production rate of manufacturer under three levels of trade credit policy for supplier–manufacturer–retailer supply chain. The supplier provides a fixed credit period to settle the accounts to the manufacturer, while the manufacturer gives a fixed credit period to settle the account to the retailer and the retailer, in turn, also offers a credit period to each of its customers to settle the accounts. We assume that the supplier supplies the raw material to the manufacturer and sends back the defective raw materials to the outside supplier after completion of inspection at one lot with a sales price. The system always produces good items in the model. Also, we consider the idle times of supplier and manufacturer. Finally, numerical examples are provided to illustrate the behaviour and application of the model with graphical simulation.     

Self adaptive animation based on user perspective

In this paper we present a new character animation technique in which the animation adapts itself based on the change in the user’s perspective, so that when the user moves and their point of viewing the animation changes, then the character animation adapts itself in response to that change. The resulting animation, generated in real-time, is a blend of key animations provided a priori by the animator. The blending is done with the help of efficient dual-quaternion transformation blending. The user’s point of view is tracked using either computer vision techniques or a simple user-controlled input modality, such as mouse-based input. This tracked point of view is then used to suitably select the blend of animations. We show a way to author and use such animations in both virtual as well as augmented reality scenarios and demonstrate that it significantly heightens the sense of presence for the users when they interact with such self adaptive animations of virtual characters.     

An imperfect production process for time varying demand with inflation and time value of money – An EMQ model

The paper deals with an economic manufacturing quantity (EMQ) model for time-dependent (quadratic) demand pattern. Every manufacturing sector wants to produce perfect quality items. But in long run process, there may arise different types of difficulties like labor problem, machinery capabilities problems, etc., due to that the machinery systems shift from in-control state to out-of-control state as a result the manufacturing systems produce imperfect quality items. The imperfect items are reworked at a cost to become the perfect one. The rework cost may be reduced by improvements in product reliability i.e., the production process depend on time and also the reliability parameter. We want to determine the optimal product reliability and production rate that achieves the biggest total integrated profit for an imperfect manufacturing process using Euler–Lagrange theory to build up the necessary and sufficient conditions for optimality of the dynamic variables. Finally, a numerical example is discussed to test the model which is illustrated graphically also.     

Classification Based on Hybridization of Parametric and Nonparametric Classifiers

Parametric methods of classification assume specific parametric models for competing population densities (e.g., Gaussian population densities can lead to linear and quadratic discriminant analysis) and they work well when these model assumptions are valid. Violation in one or more of these parametric model assumptions often leads to a poor classifier. On the other hand, nonparametric classifiers (e.g., nearest-neighbor and kernel-based classifiers) are more flexible and free from parametric model assumptions. But, the statistical instability of these classifiers may lead to poor performance when we have small numbers of training sample observations. Nonparametric methods, however, do not use any parametric structure of population densities. Therefore, even when one has some additional information about population densities, that important information is not used to modify the nonparametric classification rule. This paper makes an attempt to overcome these limitations of parametric and nonparametric approaches and combines their strengths to develop some hybrid classification methods. We use some simulated examples and benchmark data sets to examine the performance of these hybrid discriminant analysis tools. Asymptotic results on their misclassification rates have been derived under appropriate regularity conditions.     

Photoresist application for the LIGA process

 Fabrication of high aspect ratio structures requires the use of a photoresist able to form a mold with vertical sidewalls. Thus the photoresist should have a high selectivity between the exposed and the unexposed area in the developer. It should be relatively free from stress when applied in thick layers necessary to make high aspect ratio structures. PMMA (Poly Methyl Methacrylate) is the photoresist of choice in the LIGA process, mainly for its ability to hold vertical sidewalls for tall structures. It is applied to the substrate by a glue-down process in which a pre-cast, high molecular weight, sheet of PMMA is attached to the plating base on a substrate. The applied photoresist is then milled down to the precise height by a fly-cutter prior to pattern transfer by x-ray exposure. The requirement that the applied layer be relatively free from stress dictates the choice of glue-down over casting. The substrate preparation steps, as well as the conditioning of the PMMA sheet prior to the glue-down, are done, in part, to reduce the stress in the glued down sheet of photoresist. The cutting of the PMMA sheet in the fly-cutter requires specific operating conditions as well as particular cutting tools to avoid introducing any stress and the resultant crazing of the photoresist. Received: 25 August 1997/Accepted: 3 September 1997     

Index selection for databases: a hardness study and a principled heuristic solution

We study the index selection problem: Given a workload consisting of SQL statements on a database, and a user-specified storage constraint, recommend a set of indexes that have the maximum benefit for the given workload. We present a formal statement for this problem and show that it is computationally "hard" to solve or even approximate it. We develop a new algorithm for the problem which is based on treating the problem as a knapsack problem. The novelty of our approach lies in an LP (linear programming) based method that assigns benefits to individual indexes. For a slightly modified algorithm, that does more work, we prove that we can give instance specific guarantees about the quality of our solution. We conduct an extensive experimental evaluation of this new heuristic and compare it with previous solutions. Our results demonstrate that our solution is more scalable while achieving comparable quality.